You can manually create an estimate and then convert it into an invoice, ttk1. Currently, QuickBooks Online (QBO) doesn't offer an automatic feature to generate invoices directly from customer purchase orders.
Here's how:
1. Select the + Create button.
2. Choose Estimate.
3. Select a customer from the Customer dropdown.
4. Set the estimate and expiration date.
5. Enter products and services you plan to sell.
6. Enter the memo and other necessary information.
7. When you're ready, click Review and send.

Once your estimate is completed, you can easily convert it into an invoice.
If you have any additional questions, please don't hesitate to reply. I'm here to help.